Method of recording and reproducing picture information, recording medium, and recording medium playing apparatus

ABSTRACT

Method of recording and reproducing picture information and a recording medium on which the picture information is recorded by the method, and an apparatus for playing such a recording medium. In addition to a coded information signal, graphic codes including picture information and audio codes made up of codes by which data can be compressed at a compression rate higher than that of the coded information signal. The graphic codes and said audio codes are inserted as the subcode of the coded information signal together with identification codes indicating whether the codes include the picture information or the audio information. At the time of playback of the recording medium, the subcode is demodulated in accordance with the identification codes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of recording and reproducing picture information and audio information on and from a recording medium such as a video disc, a digital audio disc, and so on, and a recording medium, and also relates to a recording medium playing apparatus.

2. Description of Background Information

Systems are proposed in which picture information is recorded and reproduced in the form of the subcode on and from a digital audio disc having a diameter of 12 cm, generally designated as the compact disc (referred to as the CD hereinafter). The subcode is made up of eight subcode bits, and bit groups forming the subcode are divided into eight channels denoted respectively by letters P, Q, R, S, T, U, V, and W. In the method in which the picture information is recorded and reproduced in the form of the subcode, data corresponding to picture information is configured such that a symbol is formed by 6 bits of channels R through W out of the 8 bits forming the subcode, and 98 symbols are treated as one block, as illustrated in FIG. 1. Two symbols in the 98 symbols are used as a sync signal, and 24 symbols obtained by dividing the remaining 96 symbols, by four are treated as a minimum unit of data, i.e., a "pack", which constitutes one instruction of picture processing.

More specifically, the first symbol (referred to as symbol 0 hereinafter) of the 24 symbols shows one of several modes. A symbol 1 following this symbol 0 forms instruction which indicates the sort of the instruction. Symbols 2 and 3 following the symbol 1 constitute a parity Q which is an error correction code. Symbols 4 through 19 following the parity Q constitute a data field, and include information such as color information. Finally, symbols 20 through 23 following the data field constitute a parity P which is an error correction code for protecting the information in the "pack".

On the other hand, there are four modes, i.e. "zero mode", "line-graphics mode", "TV-graphics mode", and "user's mode". The "zero mode" is provided for a case where no operation is required for pictures on the display screen, that is, the original image is to be maintained, and all data in the "pack" are 0 for this mode.

The "line-graphics mode" is provided for such a case that a liquid crystal display is provided on the front face of the player, to display notes such as an explanation of a music selection. As shown in FIG. 2, a picture area being long sideways is formed by pixels which are arranged in 288 columns and 24 rows. In other words, each row includes 288 pixels and each column includes 24 pixels. The term "pixel" stands for the minimum display element of a picture, and it is general that the picture processing is performed by using picture comprising units designated as "fonts" each of which is made up of pixels divided into 6 columns and 12 rows.

The number of "fonts" which can be displayed in the "line-graphics mode" is 48 in the lateral direction, and 2 in the column direction, and this area is designated as "screen area". For providing the scroll function, a line of "fonts" is added to the upper and lower outer peripheries and the right and left peripheries of the Screen area, to form a picture are having 50 "fonts" in the direction of row, and 4 "fonts" in the direction of column. The subcode is formed so that the picture processing is performed by using a memory having addresses each corresponding to each pixel in this picture area. In addition, the area outside the "screen area" is designated as "border".

The "TV-graphics mode" is a mode for displaying images on the TV screen, and a picture is formed by pixels arranged in 192 rows and 288 columns as illustrated in FIG. 3. The number of "fonts" which can be displayed in the "TV-graphics mode" is 48 in the direction of row, and 16 in the direction of column. Also in this "TV-graphics mode", the subcode is formed so that the picture processing is performed by using a memory having addresses each of which corresponding to each pixel in a picture area having 50 "fonts" in the direction of row, and 18 "fonts" in the direction of column, made by adding a line of "fonts" to the upper and lower peripheries as well as the right and left outer peripheries of the "screen area".

As instructions for the picture processing, there are an instruction for painting out the whole picture area by one certain color, an instruction for drawing a picture in one "font" on the screen by using two different colors, an instruction for moving the whole picture upward or sideways, and so on.

Additionally, in the 8-bit groups forming the subcode, the Q bits forming the channel Q include time information corresponding to the track length to a certain position of each information data which is recorded from the beginning of the program area of CD, and form address time data which can be used as positional data representing the recording position. On the other hand, the P bits forming the channel P form data including information relating to a pause between two music selections.

In the case of the above-described systems of recording and reproducing picture information as the subcode, it is necessary to provide a display device such as a CRT display or displaying pictures by the subcode in order to obtain information such as the explanation of the musical numbers contained in the recording medium. Thus, there have been a problem that the size of the playing apparatus can not be reduced. In order to solve this problem, it is conceivable to record and reproduce, as the subcode, audio information together with the picture information so that the information such as the explanation of the musical numbers can be provided in the form of audible information. However, since the number of bits which can be recorded as the subcode is small, it was not possible to record, as the subcode, audio information together with picture information.

OBJECT AND SUMMARY OF THE INVENTION

The present invention is based on the point described above, and an object of the present invention is to provide an information recording and reproducing system by which audio information is easily recorded and reproduced as the subcode together with the picture information.

An information recording and reproducing system according to the present invention is characterized by the steps of recording on a recording medium, in addition to a coded information signal, graphic codes including picture information, audio codes including audio information and made by codes with which the audio information is compressed at a compression rate higher than that of the coded information signal, the graphic codes and audio codes respectively being provided with an identification code indicating corresponding one of the picture codes and the audio codes, and being inserted as the subcode of the coded information signal, and at the time of play the recording medium, decoding the subcode in accordance with the identification codes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the recording format of subcode data;

FIG. 2 is a diagram showing the structure of picture in the "line-graphics mode";

FIG. 3 is a diagram showing the structure of picture in the "TV-graphics mode";

FIG. 4 is a diagram showing the structure of audio data processing instruction according to the present invention;

FIG. 5 is a block diagram showing an example of the construction of recording apparatus;

FIG. 6 is a diagram showing recording data of a composite disc;

FIG. 7 is a diagram showing the sort of recording modes;

FIG. 8 is a diagram showing the construction of "load transparency control table";

FIG. 9 is a diagram showing the correspondency between the bit pattern of TCB and the mixing ratio;

FIG. 10 is a diagram showing "load color look-up table color 0 through color 7" instruction;

FIG. 11 is a diagram showing the construction of "write font foreground/background" instruction;

FIGS. 12A through 12C, when combined, are a block diagram showing an apparatus for reproducing picture information recorded on a disc in accordance with recording and playback method according to the present invention;

FIG. 12 is a diagram showing the arrangement of FIGS. 12A through 12C;

FIG. 13 is a block diagram showing a specific configuration of the video format signal processing circuit 30 in the apparatus shown in FIGS. 12A through 12C;

FIG. 14 is a block diagram showing a specific configuration of the coded information signal reproducing and processing circuit 31 in the apparatus shown in FIGS. 12A through 12C;

FIGS. 15 and 16 are flowcharts showing the operation of processor in system controller 32 of the apparatus shown in FIGS. 12A through 12C; and

FIGS. 17 and 18A through 18C are diagrams showing pictures obtained by the apparatus shown in FIG. 12A through 12C.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

An embodiment of the method according to the present invention will be explained with reference to FIGS. 4 through 18 of the accompanying drawings.

At first, an audio data processing instruction as illustrated in FIG. 4 is set as an instruction in the "user's mode" of the four modes in the picture information recording and reproducing system using the subcode.

In FIG. 4, the symbol 0 indicates the mode, and the symbol 1 forms an instruction made of a code indicating the coding system of data in the data field which is formed of the symbols 4 through 19. The symbols 3 and 4 form a parity Q. The four bits of the channels R through U of each of the symbols 4 through 19 constitute audio data according to ADPCM (Adapted Differential Pulse Code Modulation). In addition, symbols 20 through 23 form a parity P. In this configuration, the sampling frequency of the ADPCM data is determined to be 18.9 KHz, and the compression factor of the ADPCM data is eight times as high as that of the digital audio signal recorded on CDs which is generated at a sampling frequency of 44.1 KHz and has 16 transmission bits. Thus, audio information is easily recorded as the subcode.

FIG. 5 shows an apparatus for recording the above explained codes on a recording disc by inserting the codes in the subcode.

In the arrangement shown in FIG. 5, two-channel audio signals and a video format signal outputted from a video tape recorder for example, are respectively supplied to input terminals IN₁, IN₂, and IN₃. The video format signal is supplied to an FM modulator 1. In the FM modulator 1, a carrier signal of a predetermined frequency is FM-modulated by the video format signal. An FM signal outputted by this FM modulator 1 is supplied to a multiplexing circuit 3. On the other hand, left and right-channel audio signals are supplied to an analog-to-digital converting circuit 4. The analog-to-digital converting circuit 4 is configured to perform the sampling of each of the left and right-channel audio signals at a sampling frequency of 44.1 MHz for example, to generate two digital data corresponding to two sampled values obtained by the sampling, and to output the digital data after treating them by time division multiplexing. The output data of this A/D converter 4 is supplied to a CD system encoder 6 through an error correction code adding circuit 5 which performs the interleave of the data, the error detection, and addition of codes for the error correction. To the CD system encoder 7, an output signal of the control signal generating circuit 7 and an output signal of the error detection and correction code adding circuit 8 are supplied. The control signal generating circuit 7 is configured to generate data such as a data indicating the time elapsed after the start of the supply of audio signals to the input terminals IN₂ and IN₃, and a data indicating a pause between music selections or a portion within one music selection of the audio signals.

On the other hand, output data of the graphic/instruction code generation device 9 is supplied to the error correction and correction code adding circuit 8. The graphic/instruction code generation device is configured to record a plurality of codes which are previously inputted by key operations for example, and to read-out and output desired codes. The error detection and correction code adding circuit 8 is configured to perform the interleave and error detection of the output data of the graphic/instruction code generation device 9 and the addition of the correction code.

The CD system encoder 6 is configured to form a recording signal by making the output of the control signal generation circuit 7 data of the channels Q and P, and making the output of the graphic code generating device through the error detection and correction code adding circuit 8 data of the channels R through W, and inserting those data into the digital data from the A/D converter 4. Output signal of this CD system encoder 6 is supplied to a modulator 10 and converted to an EFM (Eight to Fourteen Modulation) modulation signal. The output signal of this modulator 10 is supplied to the multiplexing circuit 3, and processed by a frequency multiplexing with the FM-modulated video format signal.

The output signal of the multiplexing circuit is supplied to an optical disc recorder of known arrangement (not shown) in which the strength of a light beam irradiated on the recording surface of a disc rotated at a constant linear velocity for example, is modulated by this signal. As a result, the graphic codes including picture information and the instruction codes are recorded on the recording disc as the subcode of the digital audio signal, in addition to the video format signal and the digital audio signal as the coded information signal.

FIG. 6 shows a composite disc 20 carrying a digital audio signal functioning as the coded information signal into which the subcode including picture information is inserted as explained above. As shown, the composite disc 20 has a first area 20a disposed in an inner peripheral area of the disc (this area being referred to hereinafter as the CD area) in which is recorded a digital audio signal with the subcode including picture information being inserted, and a second recording area 20b (this area being referred to hereinafter as the video area) containing an FM-modulated video format signal and a superimposed digital audio signal with the subcode including picture information being inserted, wherein the superimposition is performed by using a frequency multiplexing system. Since the video format signal contains higher frequency components than the PCM signal, it is necessary to rotate the disc at a higher speed of rotation during the recording of signals in the video area 20b, than during the recording of the signal in the CD area 20a. Therefore of course it is necessary, in the playing time, to reproduce the signal by rotating the disc at the higher speed during the playback of video area 20b, than during the playback of CD area 20a. The speed of disc rotation during the playback of CD area 20a is several hundred r.p.m., whereas during the video area playback the speed of rotation is two thousand plus several hundred r.p.m. for playback from the innermost periphery of that area, and is one thousand plus several hundred r.p.m. for playback from the outermost periphery of that area, so that the speed of rotation is extremely high during video area playback.

In the head portions of the CD area 20a and the video area 20b, there respectively are provided a lead-in area in which are recorded, as the subcode, index codes relating to the contents recorded in each area, such as first and second code groups formed correspondingly to each area by the repetition of index codes which respectively indicate start and end times of small portions which together constitute each area. In addition, the index codes of the audio lead-in area include information showing whether the disc itself is a composite disc or a disc of other type.

Furthermore, when the picture information is recorded as the subcode together with the audio information, it is necessary that a picture by the FM-modulated video format signal recorded in the video area and a picture by the subcode can be displayed in the same picture screen. To realize this, a method is proposed by the applicants of the present application and others, in which a code to be inserted as the symbol 0 is set as shown in FIG. 7 in order to designate an additional mode, that is, "graphic mode with motion picture" in addition to the four modes in conventional methods.

The structure of picture in the "graphics mode with motion picture" is identical with that in the "TV-graphics mode", and an instruction designated as "load transparency control table" as illustrated in FIG. 8 is provided. This "load transparency control table" instruction is an instruction for designating the mode for each pixel in picture area. Three modes are designated by this instruction, and those are namely, "transparent mode", "mixing mode", and "non-transparent mode". In these three modes, different values are selected for the mixing ratio between a video format signal obtained by the subcode and a video format signal which is recorded by multiplexing together with the coded information signal including the subcode.

The bits in the channels R through W of each of the symbols 4 through 8 and the channels R and S of the symbol 9 constitute a series of codes TCB-0 through TCB 15 which respectively designate one of modes which will be described later for each of the group of pixels to which one of colors, which are registered as color number "0" through color number "15", is allotted. FIG. 9 shows a relationship between bit patterns of the codes TCB-0 through TCB-15 and the modes designating the mixing ratio, and the mixing ratio in each mode.

In addition, the sixteen colors indicated by the color number "0" through "15" are set by a "load CLUT color 0 through color 15 (load color look-up table color 0 through color 15)" instruction. The "load CLUT color 0 through color 15" instruction is an instruction having a structure illustrated in FIG. 10, and setting the contents of a color look-up table showing the color of pre-set color numbers or foreground/background color numbers. It is necessary to designate sixteen colors in total. However, since four bits are used respectively for each of RGB to indicate a color, two symbols are required for setting one color. Therefore, eight colors are set by one "pack" at most. With this circumstances, this instruction is divided into two instructions respectively designating eight colors of the first half, and eight colors of the second half.

The instruction code for the colors of the first half, i.e. the color 0 through the color 7, is determined to be "30", and the instruction code for the colors of the second half, i.e. the color 8 through color 15 are determined to be "31". The mixing of colors for each of the color number is as follows. Red color is represented by four bits of the channels R through U of even symbols allotted to the color number. Green color is represented by four bits, i.e. two bits of the channels V and W following the channels R through U of the even symbols, and two bits of the channels R and S of odd symbols. Blue color is represented by four bits of channels T through W following the channels R and S of the odd symbols. Therefore, 2⁴ (=16) sorts of gray scales are available for each color, and preparation of 16³ (=4096) colors is possible since three colors (RGB) are used. In addition, a gray scale "0000" corresponds to the darkest state, and a gray scale "1111" corresponds to the brightest state.

On the other hand, a "write font foreground/background" instruction is used in the "TV-graphics mode", which has such a structure as illustrated in FIG. 11. This is an instruction for writing font data of the symbols 8 through 19 in positions having a row address defined by the symbol 6 and a column address defined by the symbol 7. For the pixels whose font data is "0", a color of a color number determined by the "color 0" is designated as a background color. For the pixels whose font data is "1", a color of a color number defined by "color 1" is designated as a foreground color. At the same time, sub-picture channels can be designated by using four bits of the channels R and S of the symbols 4 and 5. By this feature, as many as sixteen picture channels can be designated. Sixteen sorts of picture are previously recorded on a disc for example, and on the playing side, a desired picture chancel an be selected at the time of playing by this scheme of designating the picture channel.

FIGS. 12A through 12C show a disc player for playing a composite disc such as shown in FIG. 6. As illustrated in FIG. 12A through 12C, a disc 20 is rotated by a spindle motor 21, and information recorded thereon is read-out by means of a pickup 22. The pickup 22 incorporates therein an optical system including a laser diode, an objective lens, and photo detectors, a focus actuator for driving the objective lens in a direction of its optical axis with respect to the information recording surface of the disc 20, a tracking actuator for biasing the beam spot (information detecting point) issued from the pickup 22 with respect to the recording tracks in a direction of disc radius, and so on. The pickup 22 is mounted on a slider 23 which is movable in the direction of disc radius by a direct drive of a transmission mechanism 25 which in turn has a slider motor 24 as a source of driving force, and made by a combination of rack and pinion gears. A read-out RF (radio frequency) signal outputted by the pickup 22 is supplied to a video format signal demodulating and processing circuit 30 and a coded information demodulating and processing circuit 31 through an RF amplifier 26.

The video format signal demodulating and processing circuit 30 includes a demodulation circuit which for example demodulates the RF signal and converts it to a video format signal and a memory which stores the video format signal after digitizing it, and configured to selectively output one of the video format signal outputted by the demodulation circuit and the video format signal read-out from the memory in accordance with a changeover command from a system controller 32. The video format signal outputted by the video format signal demodulating and processing circuit 30 is supplied to a video switch 33. In addition, the video format signal demodulating and processing circuit 30 is further provided with a separating circuit which separately extracts a horizontal sync signal h, a vertical sync signal v, and control data c from the demodulated video format signal, and the separated horizontal and vertical sync signals h and v, and the control data c are supplied to each part such as the system controller 32.

On the other hand, the coded information demodulating and processing circuit is configured to demodulate the PCM audio signal in the RF signal and to generate an analog audio signal, and also to separate the subcode of the PCM audio signal to output it.

On the other hand, in the subcode outputted by the coded information signal demodulating and processing circuit 31, two bits of the channels P and Q are supplied to the system controller 32, and six bits of the channels R through W are supplied to a de-interleave and error correction circuit 52 in which the de-interleave of the six bits of the channels R through W and the error correction using the parity Q and P are performed. Output data of the de-interleave and error correction circuit 52 is supplied to a mode-instruction decoder 53. The mode/instruction decoder 53 is configured to decode the mode represented by the three bits of the channels R through T of the symbol 0 of each pack, the mode designated by the item represented by the three bits of the channels U through W of the symbol 0 of each pack, and the instruction represented by the six bits of the channels R through W of the symbol 1 of each pack, and to supply to each part signals respectively indicative of the modes and the instruction.

Furthermore, the output data of the de-interleave and error correction circuit 52 is supplied to a picture memory device 55. The picture memory device 55 includes a RAM 56 having addresses respectively corresponding to all pixels on a picture having 50 "fonts" by 18 "fonts" in the row and column directions, in which four bits of data can be sorted in each address, and a memory control circuit 57 for sensing data indicating the color number of each pixel of a picture channel in the output data of the de-interleave and error correction circuit 52 designated by a channel designation code d by using the kind of the modes and he instruction indicated by the output of the mode/instruction decoder 53 and writing them in the corresponding addresses of the RAM 56, and for reading out sequentially in a predetermined order the memory contents of the RAM 56 in accordance with horizontal and vertical sync signals h and v.

The data outputted by the picture memory device 55 is supplied to a color look-up table 58 (this table being referred to hereinafter as the CLUT). The CLUT 58 is configured to detect the "load CLUT color 0 through color 7" instruction and the "load CLUT color 8 through color 15" instruction from the output data of the de-interleave and error correction circuit 52 in accordance with the kind of the modes and the instruction indicated by the output signal of the mode/instruction decoder 53, and hold the color data corresponding to each color number, and configured to select and output color data of the color number designated by the data read-out from the picture memory 55.

The output data of this CLUT 58 is made up of three data respectively representing the level of one of the R, G, B color signals by using four bits. The three data outputted by the CLUT 58 and indicating the levels of the R, G, B color signals are supplied to D/A converting circuit 61, 62, and 63, and converted to analog signals. Output signals of these D/A converting circuits 61 through 63 are supplied to an analog-to-video converting circuit 65. The analog-to-video converting circuit 65 is configured, for example, to form a video signal of the NTSC system by the steps of obtaining a luminance signal and two color difference signals by the output signals of the D/A converting circuits 61 through 63, generating a color carrier signal by adding signals obtained by the parallel modulation of two color subcarrier signal having a phase difference of 90° by means of the two color difference signals, and combining the color carrier signal and the luminance signal by the summation, and adding sync signals thereto. By this analog-to-video converting circuit 65, the output signals of the D/A converting circuits 61 through 63 are converted to a video signal and sent subsequently.

In addition, the output data of the de-interleave and the error correction circuit 52 are also supplied to a transparency control table 66 (this table being referred to hereinafter as the TCT). The TCT 66 is based on the picture information recording and reproducing system separately proposed by the applicants of the present application and others, and configured to detect a "load TCT" instruction in the output data of the de-interleave and error correction circuit 52 in accordance with the kind of the modes and instruction indicated by the output signal of the mode/instruction decoder 53, hold transparency control bits TCB-0 through TCB-15, and output by selecting one of the TCB-0 through TCB-15 being held, corresponding to a color number indicated by the data read-out from the picture memory device 55.

The output signal of the TCT 66 is supplied to a video switch 33 as a control signal. In addition to the output signal of the TCT 66, the video format signal obtained from the subcode and outputted by the analog-to-video converting circuit 65, and the video format signal outputted by the video format signal demodulating and processing circuit 30 are supplied to the video switch 33.

In the video switch 33, the video format signal obtained from the subcode is supplied to a stationary contact x of the changeover switch 68, and also supplied to its stationary contact y through a resistor R₁. No connection is made to a stationary contact z of the changeover switch 68. The changeover switch 68 is configured to selectively output one of the signals supplied to its stationary contacts x, y, z by moving its movable contact u to be in contact with one of the stationary contacts x, y, z in accordance with a control signal issued from the TCT 66. The video format signal outputted from the video format signal demodulating and processing circuit 30 is directly supplied to a stationary contact z of a changeover switch 69 and also supplied to its stationary contact y through a a resistor R₂. No connection is made to a stationary contact x of the changeover switch 69. The changeover switch 69, like the changeover switch 68, is configured to move its movable contact u to be in contact with one of its stationary contacts x, y, z in accordance with the control signal. The movable contacts u, u of the changeover switches 68 and 69 are mutually connected. A resistor R₃ is connected between a common junction J of the movable contacts u, u and ground. A mixed signal of the video format signal obtained from the subcode and the video format signal outputted from the video format signal demodulating and processing circuit 30 is derived at the common junction J. When the movable contacts u, u of the changeover switches 68 and 69 are in contact with the stationary contacts x, x respectively, the mixing ratio of the video format signal obtained from the subcode becomes 100%, and the mixing ratio is reduced to 0% when the movable contacts u, u are in contact with the stationary contacts z, z. When, on the other hand, the movable contacts z, z are in contact with the stationary contacts y, y, the mixing ratio is equal to M which is determined by the resistors R₁ and R₂, and the resistance of the resistors R₁ and R₂ are selected so that M has a value between 20% and 80%. The signal derived at their common junction J is supplied to a video output terminal OUT₃.

The output data of the de-interleave and error correction circuit 52 is also supplied to an ADPCM demodulation circuit 90. The ADPCM circuit is configured to detect and take-in the ADPCM data in the data outputted from the de-interleave and error correction circuit 52 by the sort of the mode and instruction indicated by the mode/instruction decoder 53, and to transmit the data to a buffer memory 91 together with a write command pulse after processing it by a demodulating operation. The demodulated output data of this ADPCM demodulation circuit 90 is written in the buffer memory in accordance with the write command pulse. To the buffer memory 91, a read command pulse fs having a frequency the same as the sampling frequency of the ADPCM data, from a pulse generating circuit (not shown) is supplied, and the data written in the buffer memory 91 is sequentially read-out in accordance with this read command pulse fs. The data read-out from the buffer memory 91 is supplied to a D/A (digital-to-analog) converting circuit 92 and converted to an analog signal. The output signal of the D/A converting circuit 92 is, after unnecessary components thereof are removed by an LPF (Low Pass Filter) 93, supplied to audio switches 95 and 96 through an amplifier 94.

The audio switches 95 and 96 are respectively consisting of changeover switches 97 (99), 98 (100), and resistors R4 (R7), R5, (R8), and R6 (R9) which are connected as the video switch 33. A switch control data e is supplied from the system controller 32 to the changeover switches 97 through 100.

Audio signals of two channels outputted from the coded information signal demodulating and processing circuit 31 are supplied to each of the audio switches 95 and 96, and mixed with the audio signal obtained from the ADPCM data recorded as the subcode. Output signals of the audio switches 95 and 96 are supplied to audio output terminals OUT₁ and OUT₂.

A position detector 70 is provided in the vicinity of the path of the movement of pickup 22 along the radial direction of disc, and serves to detect when the beam spot emitted from the pickup 22 has reached a position corresponding to the vicinity of the boundary between the CD are and the video area of a composite disc, to produce a detection signal. By the generation of this detection signal, a state that the pickup 22 has reached to the video area can be detected. The position detector 70 can have a known structure including for example an optical sensor. The detection signal outputted by the position detector 70 is supplied to the system controller 32.

The system controller 32 comprises a microcomputer which consists of a processor, a ROM (read only memory), a RAM and so on. The system controller 32 is supplied with various signals and information such as the horizontal sync signal h, the vertical sync signal v, and the control data c, the P-channel and Q-channel bits in the subcode outputted from the EFM demodulation circuit 42, disc designation information from the control part 60 indicating whether the disc to be played is a compact disc or a composite disc, and mode designation information from the operation part 60, indicating whether the reproducing area is only the CD area or the video area, or both CD and video areas in the case of the playback of a composite disc. In this system controller 32, the processor executes processing of the signals inputted in accordance with programs previously stored in the ROM, and performs the control operation of each part of the video format signal demodulating and processing circuit 30, a drive circuit (not shown) for driving the spindle motor 21, the memory control circuit 57 the deriving circuit 71 for driving the slider motor, the display part 72, and the audio switches 95 and 96.

FIG. 13 is a block diagram showing a specific circuit construction of the video format signal demodulating and processing circuit 30. As shown, the RF signal from the RF amplifier 26 is demodulated at a demodulation circuit 75, then supplied to a time base correction circuit 76 and to a separator circuit 77. In the separator circuit 77, the horizontal sync signal h, the vertical sync signal v and the control data c which are contained in the video format signal are extracted. The time base correction circuit 76 consists of, for example, a variable delay element of e.g. CCD (charge coupled device) and configured to vary the delay amount of that element in accordance with a control signal from a time base control circuit 78. The time base control circuit 78 is configured to output as the control signal a signal corresponding to a phase difference between an oscillation signal and its divided signal of a crystal oscillator (VCO) 79 which oscillates, for example, in synchronism with the horizontal sync signal h extracted at the separator circuit 77, and the horizontal sync signal and the color burst signal of the video signal transmitted through the time base correction circuit 76. For more specific configuration, reference is directed for example Japanese patent application laid-open number P56-102182.

The video signal having been processed by the time base correction operation is used as one input of a selector switch 80, and also supplied to an A/D converter 82 through an LPF (Low Pass Filter) 81. In the S/F converter 82, the sampling of the video signal is performed at intervals of a predetermined period, and the thus obtained sampled values are in turn converted to digital data. The output data of the A/D converter 82 is supplied to a video memory 83 consisting of a RAM (random access memory) and so on. A memory having a capacity for storing video information of at least one field long is used as the video memory 83. Address and mode controls of this video memory 83 are performed by a memory control circuit 84. The memory control circuit 84 is configured to perform control operations for sequentially read-out data written in each address of the video memory 83 in accordance with a clock from a reference clock generating circuit 85, and for rewriting the contents of each address of the video memory 83 in response to a write enable signal which is outputted from the system controller 32. The data read-out from the video memory 83 is converted to an analog signal in a D/A (digital to analog) converter 86, and supplied through an LPF 87 as the other input to the selector switch 80. The selector switch 80 is normally held at a position a to selectively output the video format signal directly supplied from the time base correction circuit 76, and switched to a position b in response to a changeover command from the system controller 32, to selectively output the video format signal having been processed through the video memory 83.

FIG. 14 is a block diagram showing a specific circuit construction of the coded information signal demodulating and processing circuit 31. The circuit 31 is provided with a selector switch 35 which changes its switch position in accordance with the area to be played (the CD area of the video area) during the playing of a composite disc. The selector switch 35 is operated to a position a during the playing of the CD area, and to a position b during the playing of the video area, and the changeover is performed in response to a changeover command issued from the system controller 32. In the case of the composite disc, the speed of disc rotation changes extremely between the CD area and the video area, and the PCM audio signal is for example an EFM (Eight to Fourteen Modulation) signal. For the video area, the EFM signal will adversely affect on the low frequency component of the video signal treated by the FM modulation process if the digital signal is directly superimposed on the FM video signal at the time of recording. Therefore, the digital signal, i.e. the EFM signal is recorded at a level which is lower than the video carrier level by several tens of dB, although the degree of modulation is almost the same for the EFM and video signals. Thus the frequency characteristic and amplitude of a playback EFM signal will both be different, for the cases of CD area playback and video area playback respectively. However, a common demodulating system is used for the CD area playback and the video area playback. This is made possible by switching signal processing systems for the playback EFM signals of the CD area and the video area respectively.

Specifically, during playback of the CD area, the playback RF signal is an EFM signal, which is subjected to frequency characteristic compensation by an equalizer circuit 36 having a predetermined equalizing characteristic, and is amplified at a predetermined amplification factor by an amplifier 37. During the playing of the video area, on the other hand, the playback RF signal is an FM video signal which is combined with an EFM signal. The EFM signal is extracted by an EFM signal extracting circuit 38 which is made up of an LPF and so on, then is subjected to frequency characteristic compensation by an equalizer circuit 39, which has a different equalization characteristic from the equalizer circuit 36, to be then amplified by an amplifier 40, which has a higher gain than that of the amplifier 37. In this way, an EFM signal is derived whose frequency characteristic and amplitude are almost the same as the EFM signal obtained during CD area playback.

During playback of a CD disc, the selector switch 35 is held in position a.

The playback EFM signal selected by the selector switch 35 is supplied to an EFM demodulation circuit 42 which performs the demodulation process, to obtain a PCM data that is digital data including audio information of left and right channels which is for example time-division multiplexed, and the subcode. The digital data including audio information outputted from this EFM demodulation circuit 42 is supplied to a de-interleave and interpolating circuit 43. The de-interleave and interpolating circuit 43 is configured to change back, in cooperation with the RAM 44, the order of the digital data which was rearranged by the interleave operation during the recording, in turn send it to an error correction circuit 45, and to effect the interpolation of erroneous data in the output data of the error correction circuit 45 by the average value interpolation method for example, when a correction inability signal is outputted. The error correction circuit 45 is configured to perform the error correction operation by using the CIRC (Cross Interleave Reed Solomon Code), and supply the digital data to the de-interleave and interpolating circuit 43, or supply the digital data to the de-interleave and interpolating circuit 43 together with the correction inability signal when the error correction is not possible.

The output data of the de-interleave and interpolating circuit 43 is supplied to a D/A (Digital to Analog) converting circuit 46. The D/A converting circuit 46 includes a de-multiplexer which separates from each other the digital data of left and right-channel audio information combined by the time division multiplexing, and left and right-channel audio signals are reproduced. After their unnecessary components are removed at LPFs (Low Pass Filters) 47 and 48, the reproduced left and right-channel audio signals are supplied to the audio switches 95 and 96 through amplifiers 49 and 50.

Operations of the processor in the system controller 32 in the above configuration will be specifically explained with reference to flowcharts of FIGS. 15 and 16.

Assume that a composite disc is set in a playback position. When a start command is issued from the operation part 60 in this state, the processor transmits a drive command to the motor driving circuit 71, so that the slider motor 24 is driven to move the pickup 22 to an innermost peripheral position (step S1). If it is detected that the pickup 22 has reached the innermost peripheral position by means of a detector switch of any usual configuration (not shown), the processor executes a focusing operation of the pickup 22, and performs the read-in of index code information which is recorded in an audio lead-in area at an innermost peripheral area of the disc (step S2).

Subsequently, the processor judges whether or not the disc being set is a composite disc or not, on the basis of the read information (step S3). If it is judged that the disc being set is a compact disc, then the execution directly proceeds to a CD playback mode (step S4) and a playback operation is continuously performed unless any command for the programmed music selecting operation for example has been issued. Since the playback operation in the CD playback mode itself is well known, the explanation thereof is omitted here.

If it is judged in the step S3 that the disc being set is a composite disc, the processor immediately accelerates the slider motor 21 to a maximum rated speed of rotation for the video area (step S5). At the same time, the processor moves the pickup 22 toward the outer periphery of disc at a high speed by driving the slider motor 24 at a high speed (step S6).

After these operations, when it is detected that the pickup 22 has reached to the video area by the detection signal from the position detector 70 (step S7), the processor starts the playback operation of the video area (step S8). During video area playback, the processor performs the control operation for writing the video information of at least one field (or one frame) long obtained from the disc in the video memory 83. This video information to be written may be, for example, first information in the video area, or designated by an address designation through the key operation of the operation part 60.

If it is detected that the playback of the video area has been completed, in step S9, then the processor decelerates the spindle motor 21 to the maximum rated speed of rotation for the CD area (step S10). At the same time, the processor drives the slier motor 24 at a high speed, to move the pickup 22 to the innermost peripheral position of the disc at a high speed (step S11). If it is detected (step S12) that the pickup 22 has reached the innermost peripheral position by the detection output signal of the above mentioned detector switch (not illustrated), the processor starts playback operation of the CD area (step S13). Concurrently to this, the selector switch 80 in the video format signal demodulating and processing circuit 30 is changed over by the processor to the position b thereby selecting and outputting the video information which was written in the video memory 83 during video area playback. Thus, playback of as till picture is performed during CD area playback. When the completion of the CD area playback is detected by reading the information of audio lead-out (step S14), the processor initiate the driving of the slider motor 24 to move the pickup 22 to its home position (step S15) unless any operational command is present. Furthermore, a loading mechanism (not shown in the drawings) performs disc ejection (step S16), to complete the playback operating sequence.

When an interruption, for example, by a timer occurs during the execution of the main routine, the processor proceeds to a step S20 in which the processor judges as to whether or not a designation of the picture channel is performed by a key operation in the operation part 60. If it is judged, in step S20, that the picture channel is designated, the processor transits the channel designation data d indicating the designated channel to the memory control circuit 57 (step S21), and restarts the execution of the routine which was being executed immediately before the proceeding to step S20.

If it is judged, in step S20, that the designation of picture channel is not performed, the processor judges whether or not the mixing ratio between the audio signal obtained from the EFM signal as the coded information signal and the audio signal obtained from the subcode is designated by a key operation in the operation part 60 (step S22). If it is judged, in step S22, that the mixing ratio of audio signals is designated, the processor transmits the switch control data e corresponding to the designated mixing ratio to the audio switches 95 and 96 (step S23), and restart the execution of the routine which was being executed immediately before the proceeding to the step S20.

In the operating sequence described above, playback of the information recorded in the CD area of the composite disc is performed in steps S10 through S14 after the playback of information recorded in the video area in steps S1 through S9. When the "load CLUT color 0 through color 7" instructions and the "load CLUT color 8 through color 15" instructions are decoded by the mode/instruction decoder 53 during video area playback, data of designated 16 colors among 4096 colors are held in the CLUT 58.

When a picture channel is designated by the key operation in the operation part 60, the designation data d indicating the designated picture channel is supplied to the memory control circuit 57 through the operation of the steps S20 and S21.

Subsequently, by the decoding of the "write font foreground/background" instruction etc., only the picture data of the channel designated by the channel designation data d is stored in the RAM 56 by the memory controller 57. Then the picture data stored in the RAM 56 is sequentially read-out. When the picture data read-out from the RAM 56 is supplied to the CLUT 58, a color data of a color number indicated by the picture data is then outputted from the CLUT 58. A video format signal based on this color data is outputted from the analog video converting circuit 65, and supplied to the video switch 33.

If the "load TCT" instruction which is based on the picture information recording and reproducing system separately proposed by the applicants of the present application and others is decoded in this state, the transparency control bits TCB-0 through TCB-15 respectively corresponding to each color number are then held in the TCT 66. Among the TCB-0 through TCB-15 being held, one corresponding to the color number indicated by the data read-out from the picture memory device 55 is selectively outputted from the TCT 66, and the mixing ratio in the video switch 33 is designated by the output of the TCT 66. Thus, the mixing ratio between the video format signal outputted from the analog-to-video converting circuit 65 and the video format signal outputted from the video format signal demodulating and processing circuit 30 is controlled for each pixel. Consequently, a combination of pictures such as illustrated in FIG. 17 is made possible. Specifically, the mixing ratio is set to 100% for a portion corresponding to each pixel outside a region D of a picture A based on the video format signal outputted from the video format signal demodulating and processing circuit 30, and set to 0% for a portion corresponding to each pixel within the region D. On the other hand, the mixing ratio is set to 0% for a portion corresponding to each pixel outside a region D' of a picture B based on the video format signal outputted from the analog-to-video converting circuit 65, and set to 100% for a portion corresponding to each pixel within the region D' of the picture B. Then a picture C can be formed by combining the portion of the picture A outside the region D and the portion of the picture B within the region D'.

In this way, it is possible to compose a picture as illustrated in FIGS. 18A through 18C, in which a translation of a dialogue, a musical score, or an explanation of a scene, etc., obtained from the subcode is inserted into a moving picture obtained by the video format signal recorded in the video area.

Moreover, when the audio data processing instruction is decoded, the decoding process of the ADPCM data which is recorded as the subcode is performed by the ADPCM decoding circuit 90, so that the audio signal by the subcode is supplied to the audio switches 95 and 96.

In this state, if the mixing ratio of the audio signals is designated by the operation in the operation part 60, the switch command data e corresponding to the mixing ratio is supplied to the audio switches 95 and 96 through steps S22 and S23, so that the switching control of the changeover switches 97 through 100 is performed. As a result, only the audio signal obtained from the EFM signal as the coded information signal is supplied to the output terminals, or only the audio signal obtained from the subcode is supplied to the output terminals, or a signal obtained by mixing the audio signal obtained from the EFM signal as the coded information signal and the audio signal obtained from the subcode at the mixing ratio determined by the resistors R4, R5, R7, and R8, is supplied to the output terminals.

As explained in detail in the foregoing, the system of recording and reproducing picture information according to the present invention is configured such that graphic codes including picture information and audio codes including audio information which are made up of codes capable of compressing data at a compression factor higher than that of a coded information signal are recorded on a recording medium, the graphic codes and audio codes being inserted as the subcode of the coded information signal together with identification codes added thereto indicative of the picture information or the audio information, and at the time of playing of the recording medium, the subcodes ar decoded in accordance with the identification codes. Thus, audio information can be easily recorded as the subcode together with picture information, and an explanation of a music number can be obtained a picture while a user of the system is listening to the music obtained from the coded information signal, or as an audio information. Therefore, according to the present invention, an apparatus of a simple construction which does not have a display device such as a CRT display can be used for reproducing explanations of music numbers contained in the disc. 

What is claimed is:
 1. A method of recording and reproducing picture information on a recording medium comprising the steps of:inserting graphic codes, audio codes and identification codes as a subcode of a coded information signal, wherein said graphic codes include picture information, wherein said identification codes indicate whether a code is a graphic code or an audio code, and wherein said audio codes are compressed at a compression rate higher than that of said coded information signal; recording said coded information signal on a recording medium; and decoding the subcode in accordance with the identification codes when said recording medium is played.
 2. A method as set forth in claim 1, wherein said audio codes are made up of ADPCM (Adapted Differential Pulse Code Modulation) codes.
 3. An apparatus for playing a picture information recording medium on which are recorded graphic codes, audio codes and identification codes as a subcode of a coded information signal, wherein said graphic codes include picture information, wherein said identification codes indicate whether a code is a graphic code or an audio code, and wherein said audio codes comprise codes by which said audio codes can be compressed at a compression rate higher than that of said coded information signal, said apparatus comprising:a pickup means for reading signals including said coded information signal and its subcode recorded on said recording medium and generating a pickup output signal including said coded information signal; a coded information demodulating means for demodulating said coded information signal from said pickup output signal and producing an output signal therefrom; an identification code demodulating means for demodulating the identification code from the output signal of said coded information demodulating means and producing an identification code output signal therefrom; and a demodulating means for demodulating the subcode obtained from the output signal from the coded information demodulating means in accordance with the identification code produced by the identification coded demodulating means.
 4. An apparatus as set forth in claim 3, wherein said audio codes are made up of ADPCM (Adapted Differential Pulse Code Modulation) codes.
 5. A picture information recording medium on which are record graphic codes, audio codes and identification codes as a subcode of a coded information signal, wherein said graphic codes include picture information, wherein said identification codes indicate whether a code is a graphic code or an audio code, and wherein said audio codes comprise codes by which said audio codes can be compressed at a compression rate higher than that of said coded information signal.
 6. A recording medium as set forth in claim 5, wherein said audio codes are made up of ADPCM (Adapted Differential Pulse Code Modulation) codes. 